Parasitology Commons^™

An Investigation Of Entamoeba Histolytica Chitin Synthases And Other Encystation Factors In Early Encystation, John N. Talledo

All Theses

Entamoeba histolytica is a food-and-water-borne human protozoan pathogen that relies on a two-stage life cycle for successful proliferation outside of the host. E. histolytica exists in its dormant cyst form while outside of its host and converts to the motile trophozoite (amoeba) form in the small intestine. The trophozoites colonize the large intestine to cause symptomatic disease in ~10% of infections, resulting in ~100 million cases of amoebic dysentery each year. Trophozoites can convert back to the cyst form, which is shed in feces to continue the infection cycle.

Currently, there is a lack of understanding of the exact molecular …

Analyzing Antibody Immune Response In Α1,3galt-Ko Mice After Intranasal Vaccination Of Α-Gal Virus-Like Particle, Faith Brown

Honors Theses

In this study, we evaluated the immunogenicity of intranasal immunization with α-Gal-conjugated virus-like particles (VLPs) in an α1,3-galactosyltransferase-knockout (α1,3GalT-KO) mouse model that mimics the human immune response to the α-Gal epitope. The carbohydrate epitope galactose-α-1,3-galactose (α-Gal) is expressed on the cell surface of several pathogens, including Leishmania species. This molecule is absent in humans and has emerged as a promising immunogenic vaccine target. α1,3GalT-KO mice were intranasally immunized with 10 μg either Qβ-α-Gal or Qβ per nostril and boosted twice prior to sample collection. Blood and lung lavage samples were used to evaluate the antibody response. The Qβ-α-Gal group developed …

Repurposing Cyclin-Dependent Kinase Inhibitors For The Discovery Of Novel Antiplasmodial Compounds, Ritam Bhowmik

Honors Undergraduate Theses

Malaria remains a major global health burden with over 282 million cases annually and rising resistance to artemisinin-based combination therapies. Plasmodium falciparum, the most lethal malaria parasite species in humans, relies on tightly regulated cell cycle progression during replication within red blood cells. Cyclin-dependent kinases (CDKs) are central regulators of eukaryotic cell division and transcription, and several CDK-like enzymes in P. falciparum, including Pfmrk and PfPK6, are essential for parasite growth and structurally distinct from human kinases. This study evaluated whether commercially available human CDK inhibitors (CDKIs) targeting cancer pathways could be repurposed as novel antimalarial compounds. A library of …

Effects Of Desiccation On Invasive Faucet Snail (Bithynia Tentaculata) And Trematode Survival, Elise Marie Jordahl

Graduate Research Theses & Dissertations

Parasitism is one of the most common and diverse life history strategies, yet relatively little is known about the role of parasites as invasive species. Invasive species, which present one of the greatest threats to biodiversity, often need to overcome adverse environmental conditions as they establish and spread in new habitats. Invasive parasites are subject to these same conditions, though the effects may be mediated through their hosts. Here, I use an invasive snail and its trematode parasites to quantify the effects of desiccation on survival to better understand how processes of invasion play out in host-parasite systems. The faucet …

An Assessment Of Disease Risks, Population Genetics, And Spatial Ecology Of Appalachian Cottontails (Sylvilagus Obscurus) And Snowshoe Hares (Lepus Americanus) In West Virginia, Usa, Madison Leigh Miller

Graduate Theses, Dissertations, and Problem Reports (ETD)

Snowshoe hares (Lepus americanus) occupy a large range across the United States and Canada. While snowshoe hare populations are generally considered stable in the interior of their range, populations along range edges are experiencing declines, possibly driven by climate-related factors such as seasonal coat color mismatch. West Virginia represents one of the southernmost extents of the species’ range, yet little is known about the population genetic status or population sizes of snowshoe hares in the state. Appalachian cottontails (Sylvilagus obscurus) are another lagomorph species found in West Virginia. This species experienced a historical decline and currently …

Mapping Climatic And Environmental Determinants Of Parasitic Helminth Prevalence In Southeast Asia, Angelica Avisado

UNLV Theses, Dissertations, Professional Papers, and Capstones

Climate change is reshaping environmental conditions across Southeast Asia (SEA) through rising temperatures, altered precipitation patterns, and increased droughts. These changes alter transmission dynamics of neglected tropical diseases (NTDs) by shifting spatial distribution, increasing larval development rates, faster pathogen growth development, and increasing transmission rates. NTDs are a group of preventable and treatable infections that disproportionately affect more than 1 billion people globally, specifically in tropical and subtropical regions. A subgroup of NTDs, parasitic helminth infections (PHIs) - particularly schistosomiasis, soil-transmitted helminths, and lymphatic filariasis remains a public health concern in the Southeast Asian region. PHIs and their ecological responses …

Advancing Trypanosoma Cruzi N-Myristoyltransferase As A Drug Target For Chagas Disease Through In Silico Discovery And Biochemical Evaluation, Diana Citlali González García

Open Access Theses & Dissertations

Chagas disease remains one of the most persistent and neglected parasitic infections in the Americas, advancing silently through the intracellular replication of Trypanosoma cruzi amastigotes and the invasive spread of trypomastigotes. The survival of the parasite is critically reliant on protein N-myristoylation, a lipid modification catalyzed by N-myristoyltransferase (NMT). This dissertation aims to advance beyond prior studies by systematically investigating NMT inhibition across multiple biological levels, spanning from the characterization of the purified enzyme, through cellular infection models, to the global proteomic remodeling induced within the parasite, thereby evaluating TcNMT as a potential therapeutic vulnerability in T.cruzi.Recombinant TcNMT was expressed, …

In Vitro Assessment Of The Antihistomonal Activity Of Methyl Jasmonate And Jasmonic Acid, Mckayla B. Williams

Poultry Science Undergraduate Honors Theses

Histomonas meleagridis is a protozoan parasite and the causative agent of histomonosis in gallinaceous birds. There are currently no approved prevention or treatment options available for histomonosis control in the United States. Mortality in affected turkey flocks can exceed 80% which highlights the urgent need for research investigating novel strategies to mitigate histomonosis in the field. The objective of this study was to evaluate the in vitro antihistomonal and antibacterial effects of of methyl jasmonate (MeJA) and jasmonic acid (JA), two plant-derived compounds, in a xenic culture of H. meleagridis. Assays were conducted using cultured H. meleagridis (PHL strain) treated …

The Inside Scoop: Elucidating The Three-Way Relationship Between Schistosoma Mansoni, The Gut, And Vaccines, Mariam A. Mhanna

Biomedical Sciences Theses & Dissertations

Schistosomiasis is a neglected tropical disease that affects over 250 million people worldwide. This blood fluke infection burdens communities and areas with limited to no access to clean fresh water. When a host is exposed to cercariae, the infectious agent, in a body of water, it matures in the host’s circulation into adult female and male worms. Copulated adult worms migrate to the mesentery, in the case of Schistosoma mansoni, and produce eggs that can cross the intestinal barrier and get excreted in the feces to continue the lifecycle. The effects of S. mansoni infection on the host …

Ecoimmunology Of Dirty Physella Acuta Snails, Kevin Arthur Mcquirk

Biology ETDs

Research on Physella acuta, an invasive freshwater snail, reveals insights into its parasitology, fitness, and molecular biology. Morphological and molecular analyses revealed two distinct mitogenomic lineages, local (B) and invasive (A) strains of native P. acuta, both having comparable trematode infection rates, suggesting that the low infection rates observed from A in invaded regions result from "enemy release" rather than immune incompatibility. Fitness assessments showed that while lineages A and B performed similarly under laboratory conditions, rewilding experiments revealed significantly higher fitness in lineage A. Transcriptomic profiling supported these differences, with A snails showing greater immune-related gene expression and …

Spatially Resolved Transcriptomic Profiles Of Placental Cell Populations In Placental Malaria, Corina A. Mong

Undergraduate Honors Theses

Malaria remains a prevalent infectious disease that continues to cause disease-related morbidity and mortality. Despite preventative efforts, malarial pregnancies still cause birth complications, therefore emphasizing the necessity to study these adverse outcomes in malarial pregnancy. Malaria in pregnancy can lead to placental malaria (PM), which is the presence and accumulation of Plasmodium-infected red blood cells in the placental intervillous space (IVS). Even after treatment, past PM (presence of hemozoin crystals from the parasite in the placenta) can cause a chronic inflammatory response. We predicted that the activation states of the maternal monocytes and fetal macrophages differ within the placenta and …

Individual, Social, And Environmental Factors Associated With Patterns Of Parasitic Infection In Capuchin Monkeys (Cebus Imitator), Megan C. Henriquez

Dissertations, Theses, and Capstone Projects

Parasites, and the infectious diseases they carry, are thought to have significantly impacted our evolutionary trajectory for millennia. Exploring how parasites are acquired and transmitted by their hosts in wild, natural populations is integral to understanding how similar processes may have shaped host-parasite co-evolutionary relationships over time. However, parasitological studies in humans and in non-human primates have produced inconsistent results, highlighting the dynamic, nuanced, and unique relationships individual parasites have with their hosts. These relationships are largely regulated by variation in factors at host, social, and environmental levels. Characteristics unique to the host (e.g., age and sex), factors pertaining to …

Analytical Approaches For Identification Of Essential Genomes Of Plasmodium Knowlesi And Babesia Divergens, Sida Ye

Graduate Doctoral Dissertations

Apicomplexa constitute a large phylum of single-celled, obligate intracellular protozoan parasites. Notably, Plasmodium spp. and Babesia spp. are apicomplexan parasites that infect red blood cells. Plasmodium species are the causative agent of malaria and are transmitted by Anopheles mosquitoes, affecting large human populations, whereas Babesia spp., transmitted through the bite of Ixodes ticks cause babesiosis.

In this dissertation, we investigate the essential genome of these parasites using high-throughput transposon mutagenesis. Identifying the essential genome is key to finding new drug targets and understanding resistance mechanisms, a crucial pursuit given the rising resistance to frontline antimalarial drugs and the challenges …

Myxozoan Diversity And Life Cycles In Catfish Production Ponds In Mississippi, Usa, Ethan Woodyard

Theses and Dissertations

Catfish aquaculture is a critical industry in the United States and Mississippi in particular. The industry is beset by depredation, rising feed costs, competition with imports, and loss to disease. Chief among these is the myxozoan parasite and causative agent of proliferative gill disease, Henneguya ictaluri. In chapter 2, novel molecular markers for greater resolution in species identification of these parasites are provided, allowing more robust life cycle inference, species-level identifications, and inference of evolutionary relationships through molecular phylogenetic analyses. Chapters 3–5 apply the approaches developed in Chapter 2 to a broad array of taxa beyond catfish-infecting Henneguya spp. These …

Assessing The Prevalence Of Ehrlichia Spp. In Ticks Associated With Canids In Arkansas, Eva J. Berryhill

Animal Science Undergraduate Honors Theses

Canine ehrlichiosis is a disease that is commonly seen in dogs. In previous studies, the southeastern part of the United States has been identified as an area of high prevalence. Arkansas was included in the region where the prevalence is high. Changes in climate, household income, and tick population were identified as factors contributing to this high prevalence. Canine ehrlichiosis is caused by three Ehrlichia spp., which are E. canis, E. ewingii, and E. chaffeensis. Ticks are responsible for transmitting the disease, specifically R. sanguineus, D. variabilis, and A. americanum. For this study, the goal was to determine the prevalence …

African Sleeping Sickness: From Basic Biology To Future Directions, Riddhi R. Patel

All Theses

African Sleeping Sickness is a Neglected Tropical Disease (NTD) which poses a significant health risk to impoverished populations in 36 Sub-Saharan African countries. It is a devastating disease caused by the protozoan parasite Trypanosoma brucei, which is transmitted to mammals via the bite of infected tsetse flies. The disease manifests in two stages: the hemolymphatic stage and the meningoencephalitic stage. In the latter stage, it invades the Central Nervous System (CNS) and can be fatal if left untreated. It is caused by morphologically indistinguishable species of Trypanosoma brucei in both humans and animals, where in humans it is known as …

Characterizing Malaria Infections In Caribbean Lizards: Parasite Niche Expansion & Host Response, Sarah J. Pangburn

Dissertations, Theses, and Capstone Projects

Malaria is historically one of the most severe parasitic human diseases and is still responsible for over half a million deaths annually. Plasmodium species, the causative agents of malaria, are often characterized by two hallmark features of their asexual stages: the invasion of vertebrate red blood cells and the presence of hemozoin pigment as a byproduct of host hemoglobin digestion. Despite their evolutionary relatedness to mammalian Plasmodium, wildlife malaria parasites are understudied, leaving their vast genetic diversity to be explored. Lizard-infective malaria parasites, for example, include over 100 species of Plasmodium and present a diverse array of phenotypes, some …

Toxin-Like Proteins In The Venom Of Drosophila Parasitoids, Lady V. Cardenas

Dissertations and Theses

The figitid parasitoid wasps of Drosophila are gaining importance in agriculture due to their ability to kill the resilient soft-fruit pest Drosophila suzukii. Their success and infection strategies vary, and the mechanisms underlying these differences are largely unknown. Some of their venom proteins have been shown to be important in suppressing host defense. Here, we report that Ganaspis brasiliensis, a parasitoid of D. suzukii survives well on Drosophila yakuba, a host species with a strong cellular immunity, and infected flies are unable to mount a strong immune response. To predict possible toxin-like proteins in Ganaspis venoms that might suppress cellular …

Rwanda's Natural Remedies: A Fresh Look At The Fight Against Malaria, Leandre Nsabimana Ndisanze

Pomona Senior Theses

Malaria remains one of the most devastating parasitic diseases globally, disproportionately affecting sub-Saharan Africa, where Rwanda continues to face high transmission rates and rising resistance to conventional interventions. Despite decades of control efforts, the emergence of drug-resistant Plasmodium falciparum and insecticide-resistant Anopheles mosquitoes threatens to reverse recent gains. This research responds to the urgent need for sustainable and culturally relevant alternatives by exploring the therapeutic potential of Rwandan traditional medicinal plants. These indigenous remedies, long used by local healers, offer an underexplored reservoir of bioactive compounds that may provide the basis for novel antimalarial drugs.

The central hypothesis of this …

Novel Therapuetic Approaches For Chagas Disease, Juan Carlos Silva

Open Access Theses & Dissertations

Chagas disease (CD) is caused by the hemoflagellate protozoan Trypanosoma cruzi. This disease is considered one of the 20 neglected tropical diseases (NTD), and it is estimated that 6 to 8 million people worldwide are diagnosed with CD. In the United States, Chagas infection is not reported in all states; however, most reported CD cases are chronic infections. Chagas infection is characterized by two phases: an acute and a chronic phase. Until this present moment, no prophylactic or therapeutic human vaccine is available. However, in a recent study in a murine model, our group showed that the synthetic 20-merpeptide (DAENPGGEVFNDNKKGLSRV) …

Understanding Primate Immunity To African Trypanosomes Through The Characterization Of Trypanosome Lytic Factor Formation And Function, Sara Fresard

Dissertations, Theses, and Capstone Projects

African trypanosomes cause an annual loss of over 1 billion USD due to their economic and agricultural burden in Sub-Saharan Africa. These parasites are unicellular, extracellular parasites, that infect humans, cattle, and other livestock. Humans and some non-human primates are protected against most species of trypanosomes due to an innate immunity factor, Trypanosome Lytic Factor (TLF). This modified High Density Lipoprotein (HDL) contains two unique proteins, Haptoglobin Related Protein (HPR), a ligand to a trypanosome surface receptor, and Apolipoprotein-L1 (APOL1), the lytic component. Our overall goal is to use our understanding of primate immunity to create genetically modified cattle that …

Emotional Response In Working Memory Of Individuals With Latent Toxoplasmosis, Antonella Quimbayo

All HCAS Student Capstones, Theses, and Dissertations

Toxoplasma gondii is a prevalent parasite that infects about 30% of the world population. House cats and other felids serve as definitive hosts and acquire Toxoplasma by consuming infected prey, which are intermediate hosts. This includes rats and avians, but also large mammals such as wolves and deer. Toxoplasma gondii is known to manipulate prey behavior to enhance its transmission. For example, infected rodents demonstrates attraction to and curiosity around cat urine. Wolves infected with Toxoplasma were 11 times more likely to disperse from their pack and start a new pack. The manipulation of intermediate host behavior observed in rodents …

New Insights Into T Lymphocyte-Mediated Immunity To Toxoplasma Gondii, Claire Marie Doherty

Biology ETDs

With nearly a third of the global population infected with the protozoan, Toxoplasma gondii, this parasite sits at a unique, immune-mediated interface of health and disease. In healthy individuals, Toxoplasma results in a chronic yet asymptomatic infection of the central nervous system. This quiescent infection is the result of parasite exploitation of host immune barriers, yet Toxoplasma can quickly become an opportunistic pathogen when immunity is disrupted by illness or immunosuppressive therapies. During the HIV-AIDS pandemic, it was observed that once latent Toxoplasma infections became the cause of severe, even fatal, disease in the absence of an intact T …

One Year Follow Up Of A Cross-Sectional Study Of Hookworm Infection And Response To Deworming In Beposo, Ghana, Taylor Clarkson

Capstone Experience: Master of Public Health

Hookworms are soil-transmitted helminths that infect over 500 million people worldwide, primarily those in low-income countries. Infection with hookworm can cause anemia, malnutrition, and stunted physical and cognitive development. Deworming campaigns have attempted to combat hookworm infections in endemic areas for decades. However, there is growing variability in the effectiveness of deworming drugs, and post-treatment reinfections are abundant. There are significant gaps in our understanding of critical host-parasite factors that mediate hookworm infection, reinfection, and response to deworming treatment in endemic communities. A five-year prospective study was undertaken to better understand drivers of hookworm infection in rural Ghana and thus …

Euhaplorchis Sp. A Effect On Social Behavior And Familiarity Of Gulf Killifish (Fundulus Grandis), Hannah Bauman

All HCAS Student Capstones, Theses, and Dissertations

Trophically transmitted parasites may manipulate their hosts’ phenotype (e.g., behavior, physiology, morphology) to increase the likelihood of transmission to the definitive host. In fishes, stable social groups develop familiarity over time through repeated interactions among individuals, and social preferences are often developed due to familiarity. Consequently, fishes often shoal with familiar fishes, a behavior that is likely to be protective against predation. Parasites may alter fish social dynamics in two ways: by decreasing association with familiar individuals, thereby isolating infected fish and making them more susceptible to predation by definitive hosts; and/or by incentivizing uninfected individuals to avoid infected fish …

Preliminary Investigation Of Differences In Host Mitochondria Membrane Potential During Toxoplasma Gondii Infection, Bryan L. Ortega

USF Tampa Graduate Theses and Dissertations

Toxoplasma gondii is an obligate intracellular protozoan with a broad host range of hosts, including various warm-blooded mammals, including humans. While infections can often be asymptomatic in immunocompetent individuals, they can pose significant risks to those who are immunocompromised, as well as pregnant women. Toxoplasmosis represents a significant burden on public health in the United States, with over 800,000 annual infections reported, often leading to severe complications such as symptomatic eye disease and congenital infections. Recent attention has developed regarding its potential association with human neuropathies such as Alzheimer's disease, dementia, and mood disorders. This project investigated differences in host …

Avian Symbionts Of Sulawesi: Identifying And Correlating Malaria Parasites And The Microbiome In Communities Of Endemic Avian Hosts, Rachael Joakim

Dissertations, Theses, and Capstone Projects

Since the evolution of complex organisms, there have been communities of symbionts inhabiting them. Thanks to the development of parallel sequencing techniques, DNA of entire microbial communities can be sequenced from a single sample. Some microbes can be parasitic in nature, such as Haemosporida, an order of eukaryotes causing malaria. While most symbionts form a more commensal host relationship in wild systems, host-symbiont dynamics can vary in pathogenicity based on biotic and abiotic factors. In vertebrates, microbial communities in the gut play a major role in host function, including immune responses to Haemosporida. Though this relationship is most commonly explored …

High Prevalence Of Trypanosoma Cruzi Infection In Raccoons (Procyon Lotor) And Associated Risk To Humans In Central Illinois, Esther Onuselogu

Masters Theses

Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, remains a neglected tropical disease and a growing health threat in the United States. Raccoons (Procyon lotor) often coexist with humans in urban and suburban areas and serve as reservoir hosts for T. cruzi. While T. cruzi is rare in humans and domestic animals in the U.S., it is common in wildlife species, particularly raccoons and Virginia opossums (Didelphis virginiana). This study aimed to assess the prevalence of T. cruzi infection in the raccoon population of Central Illinois and evaluate the risk of transmission to humans. …

Distribution Of Tick Species On Free-Ranging Ungulates In Northern New England, Karisa Graham

Honors Theses and Capstones

In Northern New England, ungulates are often parasitized by ticks, which is one of the leading causes for the decline in population. Ungulates are a good host for ticks, specifically deer ticks and winter ticks, and these ticks cause many tick-borne diseases in humans as well. The purpose of this study was to assess passive sampling from harvested animals as a means of tick surveillance in Vermont and New Hampshire. Ticks were collected from deer and moose and mapped throughout the two states by ArcGIS to visualize the trends in distribution. Relative abundance was greater in southeastern Vermont, with no …

Genomic Studies Of The Equine Bloodworm, Strongylus Vulgaris, Nichol Ripley

Theses and Dissertations--Veterinary Science

Strongylus vulgaris is the most pathogenic nematode parasite of grazing horses worldwide. This gastrointestinal parasitic nematode is in the family Strongylidae under the subfamily Strongylinae, or Strongylins. While the epidemiology, complete life cycle, and high pathogenicity of the fourth and fifth larval stages of S. vulgaris are well established, we understand very little about its biology. This parasite is renowned for its unique life cycle and capacity to cause arterial damage, leading to significant health and economic impacts for the equine industry. It also is the most intensively documented Strongylin; however, S. vulgaris has yet to gain drug resistance as …